A nasal spray of the ‘love hormone’ oxytocin could banish tinnitus — the ringing or buzzing in the ears that affects around seven million Britons. Also known as the ‘cuddle’ hormone, oxytocin is released by the brain into the bloodstream during social behaviours, such as hugging or kissing. Scientists think the hormone could help to treat tinnitus by damping down activity in parts of the brain responsible for producing the constant sound. An initial study found the spray significantly reduced symptoms, and now a second trial is planned in America. Many of us suffer temporary tinnitus that lasts no more than a few hours, often due to a cold or after a loud concert, which can cause some damage to the cells in the ear. But for around one in 100 people, it becomes a long-term affliction — studies show up to one in five experiences suicidal thoughts caused by the noise. When the ears are exposed to loud noise or infections, the tiny hair cells that transmit sounds to the brain become stressed and start to emit excess quantities of a brain chemical called glutamate. Called a ‘glutamate storm’, this over-stimulates nerve cells in the inner ear to the point where they eventually die. These nerve cells usually send sound impulses up to the auditory cortex, the part of the brain which processes noise. When they die, it leaves nerve cells in the auditory cortex in a permanently switched-on state, where they constantly relay sound to elsewhere in the brain. We then ‘hear’ this inside our heads as ringing or buzzing, even when there is no signal from the ear. By this point, the tinnitus is no longer being caused by the damaged ear cells but is rooted in the brain itself, and is therefore more difficult to treat. There is no cure. Instead, treatments include meditation to ease stress, as stress can make symptoms worse, or sound therapy, to distract patients’ attention from the tinnitus. The nasal spray, which is used four times a day, could be a more effective solution. Previous studies have shown oxytocin nasal sprays can potentially treat everything from flagging libido to behavioural problems caused by autism in children. Side-effects include headache, blurred vision and, more rarely, heart rhythm problems. In 2017, researchers from the Federal University of Sao Paulo, Brazil, tested the spray on 15 tinnitus sufferers over ten weeks. The results, published in the journal Frontiers in Neurology, showed a significant decline in symptoms measured on the Tinnitus Handicap Inventory — a scoring system from zero (slight ringing that does not interfere with daily life) to 100 (‘catastrophic’ ringing that disturbs sleep and daytime activities). Average scores dropped from almost 60 (severe) to below 40 (moderate). Now, in a new trial at New York University, 30 patients will be given either oxytocin nasal spray or a placebo to use four times daily for six months. The results are expected by June next year. It’s not clear how the cuddle hormone works, but one theory is that it reduces activity in two regions of the brain — the auditory cortex and the amygdala — that play a big part in generating the internal ringing noise. Dr Will Sedley, a lecturer in neurology and a tinnitus researcher at Newcastle University, says: ‘If the spray works it would be great news. Not only is the cost moderate, but it’s a well-established medication that appears to be safe.’ Source
